Four people were rushed to hospitals after a medical helicopter crashed near the expressway Saturday night.

The crash happened at about 9:15 p.m.near the I-57 and I-94 merge and the pilot managed to avoid the expressways and land in a grassy area. Authorities praised the pilot for strategically landing the chopper to avoid other potential injuries.

Four people were on board the medical helicopter, a patient, a pilot and two crew members when it went down at 9:15 p.m. The patient remains in critical condition and the others have been stabilized.

Two of the patients were taken to Advocate Christ Medical Center and the other two were taken to the University of Chicago Hospital.

The medical helicopter was on the way to Gary Airport. Authorities said the pilot made a mayday call before the crash.

Witnesses said they saw the helicopter spiraling out of control and on fire.

"As we were heading to the gas station by the school, we heard a like real loud noise that sounded like a motorcycle...We looked up to the sky, we saw the helicopter spinning around trying to keep control. As it was doing that, it was on fire. It took a real sharp turn from where it was at, it look like it was going to head more north, and then all of a sudden it was heading this way. We rushed to our car saw real quick and from Wentworth you can see where it crashed down landing," said witness Andres Herrera.

The crash could have been a lot worse. Not only did the pilot avoid the expressways but also a CTA station not far from the crash.

The ramp from I-57 onto I-94 remains closed Sunday morning for the investigation.

Investigators are on the scene to determine the cause of the crash.

Federal Aviation Administration officials were en route to investigate the cause of the crash.

The helicopter was a Eurocopter 135 air ambulance, according to the FAA.

Superior Air released a statement saying in part, "At Superior, we are working quickly to gather additional information. In the meantime, our immediate concern is for the well-being of our crewmembers and the patient that was being transported. All are currently in the care of medical professionals. and we have specially trained team members assisting them directly...A company team of experts has been assembled and will be dispatched to the accident site to participate in an investigation, along with federal aviation authorities and the manufacturer of the helicopter...We thank everyone who has expressed support to our company, and we thank everyone for their understanding during this time."